Bulgaria: Operating a Business

Ednolichen Tatgovetz or E.T. (sole proprietorship)

Number of partners: 1 person
Capital (max/min): No minimum capital required.
Shareholders and liability: No distinction between the individual and the society. The responsibility of the entrepreneur extends to his personal patrimony.

Druzhestvo s ogranichena otgovornost or O.O.D. (Private Limited Company)

Number of partners: Minimum 2 partners. 1 member for a sole proprietorship.
Capital (max/min): Minimum capital of BGN 2.
Shareholders and liability: Liability is limited to the amount contributed.

Aktzionerno druzhestvo or A.D (Joint-stock company)

Number of partners: Minimum 2 shareholders.
Capital (max/min): BGN 50,000 of which at least 25 % must have been paid at the time of incorporation.
Shareholders and liability: Liability on assets of the company and up to their value towards creditors.

Sabiratelno Druzhestvo ou S.D. (General partnership)

Number of partners: Minimum 2 partners.
Capital (max/min): No minimum capital required.
Shareholders and liability: Partners' liability is joint and unlimited

Komanditno druzhestvo ou K.D. (Limited partnership)

Number of partners: Minimum 2 partners, a sleeping partner and an active partner.
Capital (max/min): No minimum capital required.
Shareholders and liability: Active partners' liability is joint and indefinite. Sleeping partners' liability is limited to the amount contributed.

The Competent Organisation

It is possible to register a business directly on the site Invest in Bulgaria.  Formalities take between 2 and 3 weeks.

Source: Doing Business.